Insulating packaging

ABSTRACT

A package or container includes a side wall, the side wall having an inner surface and an outer surface. At least one of the inner surface or the outer surface of the side wall may be at least partially coated by a layer of a insulating material. The material may be adapted to be expanded to provide thermal insulation.

RELATED APPLICATION

The present patent application is a continuation-in-part of applicationSer. No. 11/728,973 filed Mar. 27, 2007 and which claims the benefit ofthe filing date under 35 U.S.C. §119(e) of Provisional U.S. PatentApplication Ser. No. 60/789,297, filed Apr. 3, 2006. All of theforegoing applications are hereby incorporated by reference.

BACKGROUND

Consumers frequently purchase ready-made products, such as food andbeverages, in containers. Thermally insulated containers may be designedfor hot or cold liquids or foods, such as hot coffee, iced-tea, orpizza. These containers may maintain the temperature of the liquid orfood contents by reducing heat or cold transfer from the contents to theconsumer's hand.

BRIEF SUMMARY

A package, container, or container sleeve includes a side wall, the sidewall having an inner surface and an outer surface. At least one of theinner surface or the outer surface of the side wall may include a layerof an insulating material.

Other systems, methods, features and advantages of the invention willbe, or will become, apparent to one with skill in the art uponexamination of the following figures and detailed description. It isintended that all such additional systems, methods, features andadvantages be included within this description, be within the scope ofthe invention, and be protected by the following claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a cup assembled with an outer wall.

FIG. 2 is a side cutaway view of a double wall cup.

FIG. 3 is a perspective view of an integrated container with channels.

FIG. 4 is a perspective view of an integrated container with channels.

FIG. 5 is a cross section view of a sleeve with a cup.

FIG. 6 is a top perspective view of a cross section of a cup assembledwith an outer wall.

FIG. 7 is a view of a method of making a double wall cup.

FIG. 8 is a view of a cup with insulating material applied in a pattern.

FIG. 9 is a view of a cup with insulating material applied in a pattern.

FIG. 10 is a view of a cup with insulating material applied in apattern.

FIG. 11 is a view of an outer wall disassembled from a cup.

FIG. 12 is a view of an outer wall disassembled from a cup.

FIG. 13 is a view of an outer wall disassembled from a cup.

FIG. 14 an outer wall disassembled from a cup.

FIG. 15 is a view of a cup assembled with a sleeve illustrating heattransfer.

FIG. 16 is a block diagram of an exemplary process for applying aninsulating material to substrates.

FIG. 17 is a schematic of applying an insulating material to a substratewith spray nozzles.

FIG. 18 is a schematic of applying an insulating material to a substratewith non-spray nozzles.

DETAILED DESCRIPTION

A package, container, or container sleeve may be constructed of, and/orinsulated with a insulating material. The insulating material may befixed to a container or it may be applied to a removable sleeve.Insulating material, such as thermally-expandable and/or void containingmaterial may be applied to the container or an outer wall or both.Insulating materials that are not expandable, or that are expanded inways other than by temperature may also be used, for example, pressuresensitive materials, light sensitive materials, microwave sensitivematerials and others. The insulating material may be expanded beforereaching an end user, such as when the container and/or container sleeveare manufactured, and/or the insulating material may be expanded only onend use and only in response to, for example, temperature or pressure.The insulating material may be used to aid with insulating capabilitiesof the container and/or container sleeve, and/or to add rigidity to thecontainer and/or the container sleeve, such as to reduce a thickness ofthe material components of container and/or container sleeve.

FIG. 1 illustrates a container 100, such as a cup, with an inner wall102 and an outer wall 104. The blank for the outer wall 104 may be inthe form of a container sleeve or a wall or body of a container 100. Thecontainer is not limited to a cup and may be any other container,including but not limited to, a bulk coffee container, a soup tub,press-formed containers, plate, sleeve (e.g., single face corrugated,double face corrugated, uncorrugated, cardboard, etc.), folding cartons,trays, bowls, clamshells, and others with or without covers or sleeves.The container 100 may be a cylindrical cup or a container having othergeometrical configurations, including conical, rectangular, etc. Theouter wall 104 blank is not limited to a corrugated die cut blank, andmay be constructed of any kind of paperboard, paper, foil, film, fabric,foam, plastic, and etc. The outer wall 104 may be made of any nominalpaper stock, including but not limited to, natural single-face,white-topped single face, coated bleached top single-face, corrugate,fluted corrugate or any combination of these. The outer wall 104 may beremovable from the container 100 or the outer wall 104 may be adhered tothe container 100. The outer wall 104 may be adhered, for example, bylaminating the outer wall 104 blank onto the container, using a hotmelt, cold melt and/or any other adhesive or sealing mechanisms.Alternatively or in addition, the outer wall 104 blank may be adheredwith an insulating material. If the outer wall 104 is attached to thecup during manufacture, it may increase efficiency by eliminating anassembly step by the commercial end-user. Further, it may decrease theamount of storage space required by the commercial end-user, e.g.,storing one item as opposed to two.

FIG. 1 is not necessarily drawn to scale. For example, the outer wall104 may cover a larger or smaller portion of the container's 100 surfacethan illustrated. For example, the outer wall 104 may provide full bodycoverage. Increasing the surface area of the outer wall 104 may providea larger insulated area as well as a larger print surface. Although thedrawing illustrates the outer wall 104 on a cup, the outer wall 104 maybe added to any other containers, such as but not limited to, a bulkbeverage container, press-formed container, and soup tub. Alternativelyor additionally, the outer wall 104 may be added to a container sleeve.

FIG. 2 is a side cutaway view of a container 100, which may be a doublewall cup. The container 100 may provide a jacket of air 200 between anouter wall 104 and contents 206, such as a hot or cold beverage or food,of the container 100. The air jacket 200 may provide thermal insulationas measured by an outside surface temperature T₀. The air jacket 200 maypartially or completely surround the container 100. When the container100 is grabbed, a pressure exerted on the outer wall 104 may act tocollapse the outer wall 104 at pressure points to reduce the air jacket200 and potentially initiate contact with an inner wall 102 of thecontainer 100. The air jacket 200 may collapse under pressure points andmay give a sense of low rigidity, and the contact may create hot spotson the outer wall 104.

An insulating material 216 applied between the inner wall 102 and theouter wall 104 may reduce or eliminate this effect. If a sufficientamount of insulating material 216 is used, the insulating material 216may act to provide rigidity without compromising the thermal insulationof the air jacket 200 to the outer wall 104 such that the outer wall 104does not collapse, completely or partially. The insulating material 216may add mechanical strength to the container 100. Lighter weightmaterials may be used to produce the container 100 due to mechanicalstrength added by the insulating material 216, such that the source of asubstrate forming the container 100 may be reduced. The insulatingmaterial 216 may be applied in spots, such as dots, or another pattern,either on the inner wall 102, the outer wall 104, or both, such that theinsulating material 216 defines an air gap 200 and prevents the outerwall 104 from collapsing onto the inner wall 102 under holding pressure.The insulating material 216 may also provide a rigid feel to the user,while allowing a reduction of a substrate material, for example theinner wall 102 or outer wall 104.

The insulating material 216 may expand when activated, or may bepre-expanded, for example, by the inclusion of air or inert gas, in situair voids, microspheres, expandable microspheres or other foamingagents. The insulating material 216 may be activated by, for example,temperature, pressure, moisture, or otherwise. In one example, theinsulating material 216 may be thermally-activatable, by a hot or coldtemperature. The insulating material 216 may be an expandable insulatingmaterial or adhesive. Additionally or alternatively, the insulatingmaterial 216 may include but is not limited to, binder, expandablemicrospheres or other micro-encapsulated particles, pigment and otheradditives, adhesives (e.g., hot melt, pressure sensitive), inert gasfoamed hot melt, aqueous coating containing heat expandablemicrospheres, starch-based adhesives, natural polymer adhesives, PVC,foam coatings, biodegradable glues, or any combination of these or othermaterials. The insulating material 216 may include in-situ air voids,microspheres, microparticles, fibers, expandable fibers, dissolvingparticles, and etc. The insulating material 216 may be biodegradable,compostable, and/or recyclable.

The insulating material 216 may be expandable when wet or dry. Theinsulating material 216 may include any synthetic or natural materialincluding aqueous based, solvent based, high solids, or 100% solidmaterials. The amount of solid content is typically 30% to 80% of thematerial, and more preferably 40% to 70%. Additional ingredients may beadded to the binder and/or insulating material 216, including but notlimited to, pigments or dyes, fillers/extenders, surfactants fordispersion, thickeners or solvents to control viscosity for optimizedapplication, foaming agents, defoaming agents, additives like waxes orslip aids, etc. Alternatively, the binder and/or insulating material 216may be an adhesive. The insulating material 216 may have severalproperties, including but not limited to thermal insulation to keepcontainer contents hot or cold, absorption of condensation and/orliquid, and/or it may expand on contact with hot material (such as, over150° F.), and preferably remains inactive before a determined designedactivation temperature, such as at about room temperatures. Theinsulating material 216 may be repulpable, recyclable, and/orbiodegradable.

In a further example an inert gas, such as nitrogen gas, may be injectedinto the insulating material 216. For example, an inert gas, such asnitrogen gas, may be injected into a hot-melt adhesive, starch-basedadhesive, or natural polymer adhesive may be used. The gas may beapplied onto the outer surface of the inner wall 102 before placing theouter wall 104 to give these materials foam structure, and thereforeimprove the mechanical and thermal insulation properties of the doublewall container. The gas may be injected into the insulating material216, for example, before it is applied to the outer wall 104, or duringapplication to outer wall 104.

Alternatively or additionally, the insulating material 216 may be acoating or adhesive that is combined with a blowing agent or foamingagent. The blowing or foaming agent may generate a gas upon heatingwhich may activate the insulating material 216 to assume, for example,air voids, a cellular structure, or otherwise. Alternatively, theblowing or foaming agent may be a material that decomposes to release agas under certain conditions such as temperature or pressure. Heatingmay occur during filling of the container with contents 206, such as hotfood or beverage. Alternatively, heating may occur from an externalsource—such as a microwave or water bath.

FIGS. 3 and 4 illustrate a container 100 with an outer wall 104. Thecontainer 100 may be constructed as a double-wall cup assembly. Thecontainer 100 may be a cylindrical cup, container sleeve or containerhaving other geometrical configurations, including conical, rectangular,etc. The outer wall 104 may fully or partially cover the body of thecontainer 100. The container 100 and outer wall 104 may be integratedinto a double wall cup and the insulating material 216 and/or adhesivemay be applied between the inner wall 102 and the outer wall 104. Theinsulating material may additionally have adhesive properties and thusmay form the only attachment between the container and the blank. Theouter wall 104 may be made of any nominal paper stock, including but notlimited to, natural single-face, white-topped single face, coatedbleached top single-face or any combination of these. Alternatively oradditionally, the outer wall 104 may be made with foil, film, fabric,plastic, or other materials. The outer wall 104 and/or container may berepulpable, recyclable and/or biodegradable.

The outer wall 104 may include, for example, corrugated, flute (e.g.,E-flute, F-flute, N-flute, or G-flute) uncorrugated or embossed airchannels. The air channels may be in a vertical, diagonal, or otherdirection and may channel heat away from the hands. Additionally oralternatively, air channels may arise from the application of theinsulating material 216. For example, the insulating material 216 may beapplied to the outer wall 104 in a striped, swirled, or dotted patternsuch that air channels are formed or expanded before, during or afteractivation by, e.g., heat or pressure. The insulating material 216 mayinclude blowing agents, foaming agents, and/or other agents that, uponactivation, dissolve, generate gas, or disintegrate, and thus create airvoids or foam structure.

The outer wall 104 may be removable from the container 100, such as asleeve, or the outer wall 104 may be adhered to the container 100, suchas in a double wall container. For example, a double wall container,such as a cup, or a double wall container sleeve may be manufactured bylaminating the outer wall 104 onto the container or container sleeveblank, using an insulating material 216 (e.g., void containing, foamed,or other) to secure the insulating material 216, or may be secured byany other adhesive or sealing method. If the outer wall 104 ispermanently attached to the container 100 during manufacture (e.g.,creating an integrated double wall cup or double wall sleeve), it mayincrease efficiency by eliminating an assembly step by the commercialend-user. Further, it may decrease the amount of storage space requiredby the commercial end-user, e.g., storing one item as opposed to two.

The outer wall 104 may be removable from the container. For example, adie cut blank, such as a sleeve, may be manufactured to be storedseparately and removable from the container 100.

The outer wall 104 may remain open ended on one side or on opposingsides, which may permit airflow. For example, in FIG. 3 the containermay contain openings 302 near the top of the outer wall 104. Forexample, in FIG. 4, the container may contain openings 402 near the topor bottom 404 of the outer wall 104. The opening may be formed into theouter wall 104, for example as holes, and air channels may be createdallowing air flow when the space between the inner wall 102 and theouter wall 104 is expanded by activation of the insulating material 216.Airflow may be further manipulated, for example, upward and away fromthe holding fingers by corrugated, flute corrugated, or other airchannels created by the interaction of the insulating material 216 andthe outer wall 104 or expandable material application pattern 216. Forexample, the pattern of application of the insulating material 216 maycreate air channels 304, 402.

FIG. 3 illustrates an alternate non-limiting example of how applicationof the insulating material 216 may form openings 302 near the top 306 ofthe container 100. The channels may be formed by expansion of theinsulating material 216. There may be openings on opposing ends of thecontainer 100, such as at the top 306 and the bottom 308. The openingsmay be formed by wrapping the outer wall 104 on the container withoutcompleting the seal at the top 306 or bottom 308.

FIG. 5 illustrates a cross section of an outer wall 104, such as asleeve, assembled with the container 100. This figure is meant to beillustrative and not limiting. The cup may be replaced with anycontainer, for example, a press-formed tray, a soup tub, or a bulkbeverage container. The outer wall 104 may have an inner face 506 and anouter face 504. An insulating material 216 may be applied to the innerface 506, the outer face 504, and/or to a surface between 502 the innerface 506 and the outer face 504, such as to an inner wall of the sleeve.The inner face 506 and outer face 504 do not necessarily contain a space502 between.

A insulating material 216, such as an expandable material, may beapplied to an inner face 506 of the outer wall 104 in an inactive form.The inactivated insulating material 216 may be applied as a thin filmthat does not materially alter the thickness of the outer wall 104.Applying the insulating material 216 to the inside of the outer wall 104may also maintain the printability of the outer face of the outer wall104. If the inactivated insulating material 216 on the outer wall 104 isassembled, for example, with a standard paper cup, it may maintain theslim profile of the cup. Maintenance of the slim profile may retain theefficient nesting qualities of a standard cup, allowing it to beefficiently cased, crated and shipped. Additionally, activation of theinsulating material 216 at end use may create manufacturing efficienciesby reducing the activation or foaming or curing step duringmanufacturing of the container or sleeve and thereby also reducingenergy used during manufacturing.

The insulating material 216 may be activated and thereby expanded by,for example, adding contents 206, such as hot liquid, beverage or foodinto the container 100. Alternatively or additionally, the container 100may be prefilled with contents 206, such as beverage or food and theinsulating material 216 may be activated upon heating such as bymicrowave or water bath. Activation may occur only at the consumptionstage and not at the processing stage of the outer wall 104, such thatthe outer wall 104 may be shipped to the consumer with a substantiallyinactivated insulating material 216. For example, the activation pointof the insulating material 216 may be about 120° F. or higher and/orless than 60° F., such that the insulating material 216 may be activatedonly by the temperature of hot (or cold) liquids, beverages, or food andnot activated by ambient or body temperature. The activation may causethe expandable material to expand and “push back” the outer wall 104from the container 100 creating an increased air gap. The air gap maycreate a thermal barrier between the hot beverage container 100 and thehand of the consumer. The activation may also enhance the stiffnessand/or rigidity of the container, which may allow for a reduction in thematerial or thickness of the container wall. As described in more detailbelow, the insulating material 216 may also be activated, or at leastpartially activated, before reaching the consumer. Consequently, thisability of the insulating material 216 to respond to target temperaturecan make the container or sleeve “smart” in the sense that it canincrease its insulation as the packaged content 206 gets hotter.

The insulating material 216 may be applied to the outer wall 104 in anunexpanded state. Expansion of the insulating material 216 may not occuruntil activated by adding hot fluid or solids, such as at the point ofserving. This may be different from expanding the material duringmanufacture of the outer wall 104. Expansion during manufacture mayincrease the bulk of the outer wall 104. The insulating material 216 maybe controlled to effect nesting efficiency. The properties of theinsulating material 216 may be further controlled by, for example butnot limited to, combining a outer wall 104 constructed from flutedcorrugate material with patterned application of insulating material 216to provide specific insulation, air flow characteristics and containerrigidity enhancement. For example, the corrugation and/or the pattern ofinsulating material 216 applied to the outer wall 104 may direct heatconvection upward, and may therefore reduce heat transfer horizontallytoward the holding hand of consumer. Alternatively, the insulatingmaterial 216 may be extruded into a sheet to which a pattern may beapplied, such as by fluting, die-cutting shapes, lines, channels, orother markings into the sheet before attaching the sheet of insulatingmaterial 216 to an outer wall 104. In other implementations, expansionmay occur before shipping, such as before, during or after themanufacturing of the container 100.

FIG. 6 is an exemplary top view of a cross-section of a container 100assembled with an outer wall 104. This figure is illustrative only andnot limiting. The insulating material 216 may be applied to an outerwall 104. For example, the insulating material 216 may be appliedbetween the outer wall 104 and the wall of the container 100 and mayform an integrated two-layer cup with thermally-activatable insulatedexpandable material in between, or between an outer wall 104 and aninner wall of a container sleeve. The insulating material 216 mayinclude, for example, insitu air voids, or expandable microspheres orfoaming agents 602 dispersed in a binder or any other suitable materialdisclosed above and may include an adhesive property.

FIG. 7 illustrates an exemplary method of applying the insulatingmaterial 216 to a container 100. The method may be adapted to a cupwrapping machine. In this example, the insulating material 216 may beapplied continuously or intermittently via an applicator 706 such as anozzle, glue gun, or slot die applicator onto the outside of, e.g., apaper cup 100 which may be secured to a mandrel 702. The pattern may bemanipulated by movement of the container 100 relative to the applicator706. For example, the mandrel 702 may be spun and/or moved up or down orin another direction to achieve a desired pattern, e.g., spiral, dotted,lined, and etc.

Alternatively or additionally, the applicator 706 may move relative tothe container 100 to achieve a desired pattern. For example, mandrels702 may be arranged on a rotating arm 700. Containers 100 such as cupsmay be loaded onto the mandrel 702 manually or by machine feed. The arm700 may move the container 100 proximate to the applicator 706. Theapplicator 706 may apply patterns of insulating material 216 to thecontainer 100 by moving relative to the container 100. The mandrel 702may also move the container 100 relative to the applicator 706, such asby rotation. As an example, stripes may be applied to the cup by side toside movement of the applicator 706 combined with rotational movement ofthe mandrel 702. The spray from the applicator 706 may be constant orintermittent and may create broken lines, stripes, dots, or ellipses offoam. Swirls may be applied by constant spray from the applicator 706combined with side movement and rotation of the mandrel 702.

The applicator 706 may be attached to a line which may deliver theinsulating material 216. Gas, such as nitrogen gas, may be added to theinsulating material 216 by a separate line and mixed in the applicator706, or during application, or in the applicator feed line, orotherwise.

After the insulating material 216 has been applied, the arm 700 may movethe container 100 to a different position where the cup may be removedfrom the mandrel for further processing. For example, an integrateddouble wall container, such as a cup, may be formed by inserting thecontainer 100 into an outer wall 104. The outer wall 104 may bepreformed and located in a cavity 704 into which the container 100 maybe inserted.

FIG. 8 illustrates an exemplary outer wall 104 blank. This drawing isillustrative and not meant to be limited to a size or shape. The sizeand shape may be adapted to the dimensions of any container. Aninsulating material 216 may be applied to the outer wall 104. Theinsulating material 216 may be applied by a number of methods, such asbut not limited to, a nozzle spray gun, printing, a slot coater, orother methods, such as those described above or in more detail below.Alternatively or additionally, the insulating material 216 may beextruded into a sheet and may be applied to a container, containersleeve, or die cut blank by laminating the sheet of insulating materialto the blank of the container, container sleeve, or die cut blank. Theinsulating material 216 may be applied to the outer wall 104, forexample, on an in-line cup wrapping machine, in-line on a folder/gluer,or by other suitable methods, such as off-line coating and drying. Theinsulating material 216 may be applied to the outer wall 104 in anysuitable pattern, such as but not limited to, banded, dotted, waved,squares, circles, diamonds, random, a combination of these or any otherpattern. For example, the insulating material 216 may be applied in apattern that manipulates air flow and/or conducts heat, for example,vertically upward away from the holding fingers. The insulating material216 may be applied such that it forms channels, or expands to formchannels on activation. The channels may direct natural convection. Theinsulating material 216 may fully or only partially cover the surfacebeing coated.

The outer wall 104 may be removably or permanently attached to acontainer 100 or cup by, for example, wrapping the outer wall 104 aroundthe container 100. For example, a double wall cup or container 100 maybe manufactured by laminating the outer wall 104 onto the container,using an insulating material 216 such as a starch based material, a hotmelt and expandable material, an expandable material with adhesiveproperties, a combination of these or any other adhesive or sealingmethod. If the outer wall 104 is permanently attached to the container100 during manufacture (for example, creating an integrated double wallcup), it may increase the efficiency of using an outer wall 104 byeliminating an assembly step by the commercial end-user. Further, it maydecrease the amount of storage space required by the commercial end-user(storing one item as opposed to two). The shape of the outer wall 104 inthe drawing is not meant to be limiting. The shape of the outer wall 104may be adapted to the shape of other containers, for example but notlimited to, a container sleeve, a soup tub, press-formed container, orbulk beverage containers. Alternatively the container 100 may be acontainer sleeve that is open on both ends.

The outer wall 104 may, optionally, contain in-seam hot-melt or cold-setglue. If the insulating material 216 is also an adhesive, the in-seamhot-melt or cold-set may be omitted. The in-seam hot-melt/cold-set gluemay be used in addition to the insulating material 216, such as, forbonding reinforcement. The outer wall 104 may be applied to a container100, such as a cup or sleeve by, for example, wrapping, laminating, orother manufacturing processes.

FIGS. 8 through 12 illustrate many examples of an outer wall 104. Theseexamples are merely illustrative and not limiting. FIG. 8 illustratesouter wall 104 with insulating material 216 applied in a pattern 809 tochannel the release of heat. The insulating material 216 may be made of,for example, corrugated paper, such as but not limited to flutedcorrugate. Convection may be manipulated by corrugation, the pattern ofapplication of the insulating material 216, or in another suitablemanner.

FIGS. 9 through 10 illustrate other possible, non-limiting examples ofpotential patterns of insulating material 216. The patterns ofinsulating material 216 are represented by numbers 909 and 1009,respectively. The insulating material 216 may be applied in patternsother than those illustrated in FIGS. 8-10. The insulating material 216,may vary in thickness and may provide graduated flow to channel heat toopenings.

FIGS. 11-14 illustrate patterns of openings that may be used to allowair flow. Openings are represented by numbers 1112, 1212, 1312, and1412, respectively. Openings may also be located and/or include shapessuch as illustrated by numbers 1214, 1314, and 1414. There may be diecut openings at opposing ends of the blank, or only at one end. Theshapes of the openings in FIGS. 11-14 are illustrative only and notlimiting. For example, the patterns of insulating material 216 and theshape of the openings may be so arranged as to manipulate air flow, forexample but not limited to, creating a Venturi effect.

FIG. 15 is an illustrative example showing exemplary heat transfer. Thisexample is not meant to be limiting, but merely illustrative of possibleheat loss manipulation. Total heat loss of the system may be representedby the following equation:

Q ^(T)[Cal./second]=Q ₁ +Q ₂ +Q ₃ +Q ₄

Where Q^(T) is the total heat loss. Q₁ 1504 may be the heat loss due towater evaporation. Q₂, Q₃, and Q₄, represented by 1502, 1506, and 1508,respectively, may represent the convectional and conductional heat loss.

The objective of keeping contents hot may be achieved by minimizingQ^(T). The outer wall 104 may minimize Q^(T) by minimizing Q₂, Q₃, andQ₄. The low thermal conductivity of the insulating material may resultin much lower heat loss due to Q₂, Q₃, and Q₄.

The objective of preventing consumer flesh burns may be achieved by, forexample, minimizing Q₂, Q₃, and Q₄, especially Q₂, Q₃, while allowing Q₁and Q₄ to channel the unavoidable high heat flux (due to the hot liquid)vertically up or down This may be achieved by, for example, addingcorrugated grooves to the outer wall 104. The grooves may be, forexample, in a generally vertical or diagonally tilted.

Non-limiting examples follow.

EXAMPLE 1

Example 1 provides a graphical representation of how the insulatingmaterial 216 may alter thermal conductivity. The temperature on theinside of a cup may be represented by Ti. The temperature on the outsideof the cup may be represented by To. The top line, X, may represent acontainer without the coated outer wall 104. The second line, Y, mayrepresent a container assembled with a coated outer wall 104. Thisexample may illustrate that, in a container without an outer wall 104coated with the insulating material 216, the difference in thetemperature inside versus the outside of the container may be verysmall. In a container with a outer wall 104 coated with the insulatingmaterial 216, the difference in the temperature between inside andoutside may be small when the hot food or beverage is added to thecontainer. However, the food or beverage may activate the material, A,on contact, causing the material to expand. When the material expands,the difference in temperature Ti−To, may increase.

EXAMPLE 2

Example 2 illustrates temperature sensory comparison of various outerwall 104 materials coated with the insulating material 216 compared towithout the insulating material 216. The following experiment is forillustration only and is not limiting, other experimental results mightbe obtained.

An insulating material 216, such as a thermally, or other, expandablematerial may be applied to outer wall 104 blanks made of variousmaterials, such as but not limited to paper, paperboard, and flutedcorrugated paper. Each outer wall 104 blank may be wrapped around acontainer, such as a cup. The cup may be filled with hot water. The cupsmay then be handled with bare hands and a comparison made between thesensory responses to the two conditions. In each test, the cups withcoated outer wall 104 were less “hot” to the touch than those withuncoated outer wall 104. Expansion occurred within a few minutes ofpouring hot water into the cup.

EXAMPLE 3

Coatings of insulating material 216 may be applied to a single facemedium. The coating may be expanded when wet using a MASTER-MITE 120 V,475 W heat gun at 600 degrees F.

EXAMPLE 4

Coatings of insulating material 216 may be applied to the outside of a12 Oz cup and allowed to air-dry overnight. The next day, 190 degree F.hot water may be poured into the cup. Noticeable expansion may beobserved shortly after filing the 190 degree F. hot water into the cup.Lids may be placed on the cup, and after 7 minutes more expansion may beobserved, but still partial expansion. A benefit of post-heat activationmay be that the hotter the liquid the more the coating expands.

EXAMPLE 5

A coating of an insulating material 216 was applies to a cup. A 250 W IRheater manufactured by Fisher Scientific model no. 11-504-50 may be usedto heat the insulating material 216. Expansion may be slow when the lampis six inches away from the insulating material 216 and immediate whenone inch away from the insulating material 216.

EXAMPLE 6

Coatings of insulating material 216 may be applied to paper, which maythem be wrapped around a paper cup after the coating is allowed to airdry. Heat from a heat gun may be used to heat the part of the insulatingmaterial 216 coating indirectly through the paper shell for one minute.The coating expanded. Another part of the unheated insulating material216 coating may be heated under an IR lamp through the paper. Theinsulating material 216 coating expanded.

EXAMPLE 7

An insulating material 216, such as a heat expandable coating, may beapplied within the walls of a double wall sleeve or container, such as acup. During manufacture, the insulating material 216 may be adequatelydried but not expanded, or not fully expanded. When the sleeve orcontainer is exposed to high temperature, such as the temperature ofcoffee or soup, the insulating material 216 may expand pushing the wallsof the double wall sleeve or container away from each other. Thisexpansion through activation may “smartly” increase the air voids in theinsulating material 216 as well as the insulation and rigidity of thepackage. The following details an experiment illustrating how use of theinsulating material 216 decreases a weight of a material used in themanufacture of a container or container sleeve. Although the experimentemploys a limited set of materials, they demonstrate the feasibility andbenefits of the insulating material 216.

Two samples were compared. The reference container was a 16 ouncedisposable cup with a 16 pt outer wrap. The experimental container was a16 ounce disposable cup with a pattern of insulating material 216, inthis case a foam coating, and a 12 pt outer wrap. Both cups were filledwith 190 F water. The insulating material 216 of the experimentalcontainer expanded upon addition of the 190 F water. The outer surfacetemperature of each cup was measured and plotted below. The experimentalcup displayed improved insulating properties during the first fewminutes of the experiment.

A second trial illustrated the use of container sleeves. The referencecontainer sleeve was an N-flute single face sleeve. The experimentalcontainer sleeve was an N-flute single face sleeve with an inside layerof insulating material 216, in this case, foam coating. A layer of kraftpaper was laminated over the layer of insulating material 216 and thematerial was dried, but not expanded. The insulating material 216 wasapplied in two patterns: full coverage and lines running from the top tothe bottom of the sleeve. To summarize, there were five formats ofcontainer sleeves tested:

-   -   N-flute single face sleeve with inner layer of kraft paper    -   N-flute single face sleeve with inner layer of dried        non-expanded heat activatable aqueous coating (“AP”) and an        inner layer of kraft paper    -   N-flute single face sleeve with inner layer of expanded heat        activatable aqueous coating and no layer of kraft paper    -   N-flute single face sleeve with inner layer of expanded heat        activatable aqueous coating arranged in vertical lines and inner        layer of kraft paper    -   N-flute single face sleeve with a full coverage inner layer of        expanded heat activatable aqueous coating and inner layer of        kraft paper

The sleeves were applied to a 16 oz disposable cup which was filled with190 F water. After filling, the temperature of the outside of the cupwas tested at one minute intervals for 5 minutes. The results arecharted below.

The cups and sleeves containing the foam coatings also had higherrigidity, even at a reduced paper stock. The patterned foamed coatingprevented even the 12 pt outer wrap from collapsing into the inner wallduring handling. This may allow the use of lower basis weight andcaliper paper board while maintaining good insulation.

FIG. 16 is a block diagram of an exemplary process for applying amicro-particle coating to substrates. The process may include applying amicrosphere or other expandable coating to any of a substrate, die cutblank, container, sleeve, catering trays, double-wall cups, press-formedtray, soup tub and bag-in-the box containers. The process may includeinline 1600 and off-line 1610 procedures. The inline procedure 1600 mayinclude stacking stations 1620, manufacturing stations 1630, andpackaging stations 1640 used for the manufacturing of the container frompaper or die cut stock. The stacking, manufacturing and packagingstations may be completely automated and/or include manual stations.

Coating application processes may occur in-line 1600 or offline 1610, atthe same or another facility. In-line application may include theapplication of the insulating material 216 at one or more of thestacking stations 1620, manufacturing stations 1630, and packagingstations 1640. The insulating material 216 may be applied in variousways, including but not limited to brushes, sponges, printing, a nozzle,spray, a slot die coater, or by lamination to an extruded sheet ofcoating. Any of these applications, or various combinations of them, mayoccur in-line 1600 or offline 1610, where the off-line process may occurbefore the stacking stage 1620.

Application with a brush or brushes may occur by feeding the insulatingmaterial with pressure through a tube to the brush. The brush may bemanufactured from different materials such as horse hair or syntheticmaterials. The brush may include hollow filaments such that theinsulating material is applied through the filaments. The brush mayapply a swatch or pattern of the insulating material. The amount ofinsulating material to the brush may be controlled such that the amountof insulating material applied to the substrate may be metered. As anillustrative and not limiting example, the amount may be controlled suchthat a 1/64^(th) inch layer of insulating material is applied, which mayexpand to 1/16 or 1/32 of an inch, or the distance of the gap between aninner and outer layer of a double-wall cup. It may be preferable thatthe insulating material does not deform a shape of the outer layer onceexpanded. The insulating material 216 may be distributed in a uniform orvarying pattern. The brush may be used for broader applications, such asto coat the inside of a bag-in-the-box container.

Application with a printing press may occur by running substratesthrough rollers. The substrates may be roll or web form of paper stock,or alternatively in sheet form. The insulating material 216 may be pressapplied in spots or patterns or with full coverage, depending on animplementation.

In FIG. 17, spray nozzles 1700 may be used to apply a insulatingmaterial 216 to a substrate 1720. The nozzles may diffuse the insulatingmaterial to apply a thin, uniform layers of the insulating material 216on the substrate. One or more spray nozzles may be used to formcontinuous or interrupted patterns of the insulating material 216. Thenozzles may be arranged such that the applied insulating materials 216overlap, are side-by-side and/or are separated by a space. The spray maybe metered to control a thickness of the applied insulating material216. The nozzle may also be positioned to direct spray of the insulatingmaterial 216 onto designated portions of the substrate, such as at acorner.

In FIG. 18, non-spray nozzles 1800 may be used to apply a stream 1810 ofinsulating material 216 to the substrate 1820. The stream may be meteredthrough the nozzle to apply a precise amount. The nozzle may be sized tocontrol a specified width and height of the stream 1810. Flow from thenozzles may be turned on and off to accommodate a specified pattern ofthe insulating material 216 to the substrate.

In a trough or a dip insulating material 216 application, substrates maybe moved through the trough that contains insulating material 216. Oneor both sides of the substrate may be run through the trough. Athickness of the insulating material 216 being applied to the trough maybe controlled by how long the substrate sits in the material. Atemperature of the insulating material 216 and substrate may becontrolled to activate or not activate the expandable insulatingmaterial 216 during the application process. A control blade may be usedto meter off excess insulating material 216. The substrates may be beltfed though the through or individually held in the through.

With any of the above application processes, and with any other process,the applied insulating material 216 may be dried or set, such as byapplying or blowing cool air or warm air without activating theinsulating material 216, if it is desired to expand the insulatingmaterial 216 in a later process, such as during manufacturing or at thetime of consumer use. The insulating material 216 may also be expandedafter manufacturing and before consumer use, such as at the stackingstation. The insulating material 216 may be expanded before or afterstacking the containers.

Coated or uncoated blanks may be fed to the stacking station. Theinsulating material 216 may be applied during in-line or off-lineprocessing. If applied in-line, the insulating material 216 may beallowed to dry before the cups, sleeves, containers, etc. are formed, orthey may be formed while the insulating material 216 is wet. Dependingon the properties of the insulating material 216, it may take a coupleof seconds to several minutes to dry. The insulating material 216 may beactivated during the in-line manufacturing or afterwards, such as at theconsumer stage. To activate the insulating material 216 in-line, any orall of infrared (IR), air, convection or conductive heating methods maybe used. The insulating material 216 may take a couple of seconds toseveral minutes to fully expand. For example, a mandrel, which holds acontainer from the inside of the container, and/or a collar, which holdsa cup from the outside of the container, may be used to apply heat toexpand the insulating material 216 during the container manufacturingprocess. If a wet or partially dry insulating material 216 contacts themandrel during process, the mandrel may be manufactured to include anon-stick material, such as TEFLON to prevent sticking or transfer ofthe insulating material 216 onto the mandrel. Lower activationtemperatures may be preferred if the activation occurs in-line. Byactivating the insulating material 216, the insulating material 216expands to form a reinforced air gap. The insulating material 216 may bepartially expanded during manufacturing of the container, and then theexpansion may continue to the consumption stage.

As mentioned, use of the insulating material 216 may help to reduce thethickness of substrate needed to make the container, sleeves, etc.,while maintaining a better rigid feel to the consumer. The insulatingmaterial 216 may also improve insulation properties of the container,and to help keep the beverages or foods warm or cold longer, dependingon the application. The substrates may be made of natural fibers,synthetic or both, such as SBS (solid bleached sulfate) paper board orbox board. A sleeve materials, such as liner and medium, may be producedof 15 LB/3000 ft² to 100 LB/3000 ft² material, and preferably 18 LB/3000ft² to 50 LB/3000 ft². The caliper of the paper substrate for hot orcold cups, soup tub, press-formed container and other non-corrugatedcontainers may range from 9 point to 24 point, and preferably 10 pointto 24 point, where a point is equal to 1/1000 inch.

While various embodiments of the invention have been described, it willbe apparent to those of ordinary skill in the art that many moreembodiments and implementations are possible that are within the scopeof the invention.

1. A double-wall container, comprising: an inner wall; an outer wallattached to the inner wall, where the inner wall and the outer wall forman air gap therebetween; and insulating material positioned between theinner wall and the outer wall; wherein the foam creates air channels. 2.The double-wall container of claim 1 where the insulating materialcomprises in situ air voids.
 3. The double-wall container of claim 1where the insulating material is foamed with nitrogen gas.
 4. Thedouble-wall container of claim 1 where the insulating material is foamedwith expandable microspheres.
 5. The double-wall container of claim 1where the insulating material is a starch based foam.
 6. The double-wallcontainer of claim 5 where the starch based foam is foamed with nitrogengas.
 7. The double-wall container of claim 4 where the expandableinsulating material accommodates a reduction in a weight of the paperstock.
 8. The double-wall container of claim 1 where the insulatingmaterial is activated to expand by a hot temperature.
 9. The double-wallcontainer of claim 1 where the insulating material is applied is astriped pattern.
 10. A method of making a double-wall container,comprising: providing a first substrate to form an inner wall of acontainer; providing a second substrate to form an outer wall of thecontainer; providing an applicator to apply insulating material to thecontainer; moving the container into alignment with the applicator;applying an insulating material to the inner wall of the firstsubstrate; and attaching the second substrate to the container to formthe outer wall.
 11. The method of claim 10 where the insulating materialis applied in a pattern.
 12. The method of claim 11 where the pattern isapplied by movement of the applicator relative to the container.
 13. Themethod of claim 11 where the pattern is applied by movement of themandrel relative to the applicator.
 14. The method of claim 11 whereinthe pattern is applied by intermittent applications from the applicator.15. The method of claim 14 where the insulating material is applied is alined pattern.
 16. The method of claim 14 where the insulating materialis applied to an outer surface of the inner wall of the first substrate.17. A sleeve, comprising: a blank having an inner surface and an outersurface; an insulating material applied to at least one of the innersurface or outer surface of the blank, where the insulating materialforms channels.
 18. The container of claim 17, where the insulatingmaterial comprises a starch based foam.
 19. The container of claim 17where the insulating material comprises in situ air voids.
 20. Thecontainer of claim 18 where the starch based material is foamed withnitrogen gas.
 21. The container of claim 17 where the material isexpanded upon manufacturing.
 22. The container of claim 17 where thematerial is expanded by a hot beverage or food.
 23. The container ofclaim 17 where the expandable material is thermally expandable.